Mark Twain once said: “If you don’t like the weather in New England now, just wait a few minutes.” He was making an unknowing reference to the , which drives the weather over North America and Europe like a high-altitude conveyor belt. But increasingly, the jet stream is taking a more circuitous route over the northern latitudes, meaning weather systems hang around longer than they used to. And a warming Arctic is probably to blame, says Jennifer Francis, a professor at Rutgers University’s Institute of Marine and Coastal Sciences. Francis – who says it’s too early to know if the well-established Arctic warming is caused by man or some natural phenomenon – was speaking during a session on Arctic change at the annual meeting of the American Association for the Advancement of Science in Chicago on Saturday.

One of the most powerful ways to figure out how the Earth will respond to all the carbon dioxide we’re putting into the atmosphere is to look back into the planet’s history. Paleontologists have spent a lot of time trying to understand a time, more tha…